1. Field of the Invention
This invention relates to an adjusting device for the sanding drum of a double-drum sander, particularly to one able to micro-adjust the rear sanding drum of a sander to move up and down to match with the size number of the emery of the front sanding drum of the sander for carrying out abrading with precision.
2. Description of the Prior Art
A conventional double-drum sander 10, as shown in FIG. 1, includes a machine frame 11, two sanding drums 12, 13 respectively installed at the front and the rear section of the machine frame 11 and a conveyer 14 located under the two grinding drums 12, 13. Generally, the two sanding drums 12, 13 have their surfaces respectively provided with coarse and fine emery to abrade an article orderly so as to achieve excellent effect of abrading of the article. Besides, to deal with articles of different thickness and control the abrading thickness of an article, the machine frame 11 of the sander 10 is provided with a hand crank 15 and a helical rod 16 connected together to be turned for adjusting the conveyer 14 to move up and down and controlling the article thereon to touch with the two sanding drums 12, 13 to an anticipated extent.
However, the two sanding drums 12, 13 of the conventional sander 10 are axially and fixedly assembled with the bearing 17 of the machine frame 11. Thus, when the axles of the two sanding drums 12, 13 are positioned at a same height, the rear sanding drum 13, which has its surface provided with fine emery and which is impossible to be adjusted to move up and down, can hardly obtain good effect of abrading of an article. If the two sanding drums 12, 13 are positioned with a fixed distance difference between them, the size of the emery provided on the rear sanding drum 13 still has to be changed in order to match with material of the article to be abraded or meet different requirements of the precision of abrading, equally failing to achieve excellent effect of abrading.
The objective of this invention is to offer an adjusting device for the sanding drum of a double-drum sander, which is provided between the opposite ends of the rear sanding drum and the machine frame of a sander for micro-adjusting the rear sanding drum to move up and down. The adjusting device has indicating graduations marked thereon, so that the rear sanding drum can be precisely adjusted to a most suitable height to match with the size number of the emery provided on the front sanding drum of the sander and carry out abrading with precision.